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Natural occurred nanotubes, halloysite nanotubes, were modified by silane and incorporated into epoxy resin to form nanocomposites. The morphology of the nanocomposites was characterized by transmission electron microscopy (TEM). Dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA) were performed on the nanocomposites. Flexural property and coefficient of thermal expansion (CTE) of the nanocomposites were also determined. Comparing with the neat resin, about 40% increase in storage modulus at glassy state and 133% at rubbery state were achieved by incorporating 12 wt% modified HNTs into the epoxy matrix. In addition, the nanocomposites exhibited improved flexural strength, char yield and dimensional stability. TEM examination revealed a uniform dispersion of the nanotubes in the epoxy resin. The remarkably positive effects of the HNTs on the performance of the epoxy resin were correlated with the unique characteristics of the HNTs, the uniform dispersion and the possible interfacial reactions between the modified HNTs and the matrix. [ABSTRACT FROM AUTHOR]

The nanocomposites of natural rubber (NR) and organoclay with unsaturated carbon-carbon double bonds (C=C) on interlayer surfaces (USMMT) are prepared by the grafting and intercalating method in latex in the presence of butyl acrylate (BA) monomer. The conversion, grafting efficiency, and grafting percentage of BA onto NR and USMMT are determined. The structure and morphology of the nanocomposites are characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmitted electron microscopy (TEM), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and swelling experiments. The mechanical properties of the nanocomposites are measured. The results show that graft copolymerization of BA monomer onto NR molecular chains can take place with high conversion, grafting percentage, and grafting efficiency. At the same time, BA can intercalate into the interlayer galleries of USMMT and polymerize in situ together with C=C bonds on the interlayer surfaces. As a result, the interlayer spacing of organaclay is increased and the interfacial combination between the silicate layers and rubber is strengthened. The results of XRD and TEM demonstrate the formation of the nanocomposites of NR-M-USMMT. The glass transition temperatures of the nanocomposites are higher than that of the NR vulcanizate. The mechanical properties of the nanocomposites are remarkably improved compared with those of the NR and NR-USMMT vulcanizate. [ABSTRACT FROM AUTHOR]

A naturally occurred microtubullar silicate, halloysite nanotubes (HNTs), was co-cured with epoxy/cyanate ester resin to form organic-inorganic hybrids. The coefficient of thermal expansion (CTE) of the hybrids with low HNT concentration was found to be substantially lower than that of the plain cured resin. The moduli of the hybrids in the glassy state and rubbery state were significantly higher than those for the plain cured resin. The dispersion of HNTs in the resin matrix was very uniform as revealed by the transmission electron microscopy (TEM) results. The interfacial reactions between the HNTs and cyanate ester (CE) were revealed by the results of Fourier transform infrared spectroscopy (FTIR) and x-ray photoelectron spectroscopy (XPS). The substantially increased properties of the hybrids were attributed to the covalent bonding between the nanotubes and the matrix. [ABSTRACT FROM AUTHOR]